fix fallback font broken when using MSDF

Source/Engine/Render2D/Font.cpp

@@ -52,6 +52,10 @@ void Font::GetCharacter(Char c, FontCharacterEntry& result, bool enableFallback)
             for (int32 fallbackIndex = 0; fallbackIndex < FallbackFonts.Count(); fallbackIndex++)
             {
                 FontAsset* fallbackFont = FallbackFonts.Get()[fallbackIndex].Get();
+                if (fallbackFont && _asset->GetOptions().RasterMode == FontRasterMode::MSDF)
+                {
+                    fallbackFont = fallbackFont->GetMSDF();
+                }
                 if (fallbackFont && fallbackFont->ContainsChar(c))
                 {
                     fallbackFont->CreateFont(GetSize())->GetCharacter(c, result, enableFallback);

Source/Engine/Render2D/FontAsset.cpp

@@ -155,6 +155,22 @@ FontAsset* FontAsset::GetItalic()
     return _virtualItalic;
 }
 
+FontAsset* FontAsset::GetMSDF()
+{
+    ScopeLock lock(Locker);
+    if (_options.RasterMode == FontRasterMode::MSDF)
+        return this;
+    if (!_virtualMSDF)
+    {
+        _virtualMSDF = Content::CreateVirtualAsset<FontAsset>();
+        _virtualMSDF->Init(_fontFile);
+        auto options = _options;
+        options.RasterMode = FontRasterMode::MSDF;
+        _virtualMSDF->SetOptions(options);
+    }
+    return _virtualMSDF;
+}
+
 bool FontAsset::Init(const BytesContainer& fontFile)
 {
     ScopeLock lock(Locker);

Source/Engine/Render2D/FontAsset.h

@@ -122,6 +122,7 @@ private:
     Array<Font*, InlinedAllocation<32>> _fonts;
     AssetReference<FontAsset> _virtualBold;
     AssetReference<FontAsset> _virtualItalic;
+    AssetReference<FontAsset> _virtualMSDF;
 
 public:
     /// <summary>
@@ -180,6 +181,12 @@ public:
     /// <returns>The virtual font or this.</returns>
     API_FUNCTION() FontAsset* GetItalic();
 
+    /// <summary>
+    /// Gets the MSDF version of the font. Returns itself or creates a new virtual font asset using this font but rasterized with MSDF.
+    /// </summary>
+    /// <returns>The virtual font or this.</returns>
+    API_FUNCTION() FontAsset* GetMSDF();
+
     /// <summary>
     /// Initializes the font with a custom font file data.
     /// </summary>